Class StandardJarScanner

The default JarScanner implementation scans the WEB-INF/lib directory
followed by the provided classloader and then works up the classloader
hierarchy. This implementation is sufficient to meet the requirements of the
Servlet 3.0 specification as well as to provide a number of Tomcat specific
extensions. The extensions are:

Scanning the classloader hierarchy (enabled by default)

Testing all files to see if they are JARs (disabled by default)

Testing all directories to see if they are exploded JARs
(disabled by default)